In the irrigation of crops, particularly lettuce, cotton and similar crops, pipes are extended laterally from main lines for the conduction of water. The laterals are built in portable sections which have means for connecting them end to end to form lateral runs of up to one-half mile. Typically each of the lateral sections has a 1inch pipe which is inserted into the lateral wall by means of threads and grooves and sealed with plumber's compound. The other end of the riser typically terminates in a sprinkler head, for example a "Rain Bird" sprinkler head which is rotated in a clock-wise direction by action of the water pressure on the sprinkler head mechanism.
A vexing problem is caused by the introduction into the irrigation water of foreign particles such as sand, grass, leaves and other debris which eventually clog the outlets of the sprinkler heads. When the sprinkler head is clogged with sediment and debris it must be cleaned to restore efficiency. This is a time consuming job. Therefore the foreign particles should be screened out before they reach the sprinkler head. Various devices in the prior art can be used to screen out these foreign particles including screens, meshes and sieve-like apertures. However, these devices must in turn be cleaned, often slowly and laboriously, to reopen the apertures for passage of water. The procedure is time consuming because each aperture must be individually cleaned out with a wire or the like.
Thus there is a need in the industry for an irrigation valve which is self-cleaning at the point of connection of the riser to the lateral to prevent the loss of time in periodic cleanings of the intake valve and the loss of efficiency when such valves and apertures are clogged with debris as above described.
An additional problem with prior art detachable valves is that they are bulky, difficult to store and to carry, and subject to breakage when loaded for carriage on a transport rack, which is the usual method of transportation from one site of use to another. In the industry it is often necessary to employ unskilled labor in the task of irrigating the fields. The workers often damage the prior art risers in the acts of assemblying, storing and transporting them. When a riser pipe is broken or damaged expense and equipment down-time are involved in repairing it. Moreover, the flow of water must be cut off at the main line when changes in the laterals for any purpose--e.g. repair or change of number of extensions--are made.
Some prior art valves are complex, having a number of moving parts such as hooks and springs and valve wheels which provide opportunities for malfunction and create an unwanted bulk in storage and transportation, and require distinct steps in hooking up the lateral and riser and turning on the flow of water.
Therefore, a further and additional need is the provision of a simplified detachable riser which can be handled easily by unskilled labor with a minimum of instructions on the function of the apparatus. This assembly should be easily portable and capable of being stored in a more compact space than heretofore found practicable for such assemblies, with a minimum exposure to breakage and malformation.